The objective of the present application is to employ the cell biology approach in an attempt to further understand the intimate structural and functional relationship among various cell types that characterize benign prostatic hyperplasia (BPH) development. The prostate consists of two basic components: STOMA and EPITHELIA. The latter can further be separated into the secretory cells and basal cells. Whether or not BPH development is associated with an altered cell-cell interaction remains to be an important question which will be addressed in this application. The use of various culture procedures permits us to examine the biological properties of individual cell types and combinations of them. Furthermore, by employing the newly developed techniques of two-dimensional gel electrophoresis and immunocytochemistry to characterize cytoskeletal proteins and prostate-associated specific proteins, we are able to assess the structural and organizational properties of various human prostatic cells in culture. The following specific aims are proposed: 1. Cultivation and characterization of epithelial and mesenchymal components from neonatal, normal, and hyperplastic human prostate. 2. Cultivation and characterization of epithelial and mesenchymal components from peripheral and periurethral zones of the human prostate. 3. Assessment of biological and biochemical properties of stromal and epithelial cells and their interactions under a variety of culture conditions. 4. Characterization of prostatic stromal and epithelial cells and their combination grown in nude mice and comparison of their biological properties with those grown in vitro.